Electrically conductive polymer suspension, electrically conductive polymer composition, solid electrolytic capacitor, and method for producing the same

Abstract

An electrically conductive polymer composition has high electrical conductivity, excellent water resistance, high density, and excellent smoothness. Also disclosed is a solid electrolyte capacitor which is prevented from the reduction in electrical conductivity, has low ESR, and also has excellent reliability. Further disclosed is a method for producing the solid electrolyte capacitor. The electrically conductive polymer composition is produced by removing a dispersion medium from an electrically conductive polymer suspension, wherein the electrically conductive polymer suspension includes: an electrically conductive polymer material including a dopant composed of a polyacid or a salt thereof and an electrically conductive polymer; at least one compound (A) selected from erythritol, xylitol and pentaerythritol; and the dispersion medium.

1 . An electrically conductive polymer suspension comprising:
 an electrically conductive polymer material comprising a dopant composed of a polyacid or a salt thereof and an electrically conductive polymer;   at least one compound (A) selected from erythritol, xylitol and pentaerythritol; and   a dispersion medium.   
     
     
         2 . The electrically conductive polymer suspension according to  claim 1 , wherein the electrically conductive polymer material comprises, as the dopant, a polysulfonic acid or a polycarboxylic acid. 
     
     
         3 . The electrically conductive polymer suspension according to  claim 2 , wherein the electrically conductive polymer material comprises, as the dopant, a polystyrene sulfonic acid or a polyester sulfonic acid. 
     
     
         4 . The electrically conductive polymer suspension according to  claim 1 , wherein the electrically conductive polymer material comprises, as the electrically conductive polymer, a polymer obtained by polymerizing at least one monomer selected from a group consisted of pyrrole, thiophene, aniline and derivatives thereof. 
     
     
         5 . An electrically conductive polymer composition obtained by removing the dispersion medium from the electrically conductive polymer suspension according to  claim 1 . 
     
     
         6 . The electrically conductive polymer composition according to  claim 5 , wherein removing the dispersion medium is carried out at the melting temperature of the compound (A) or higher. 
     
     
         7 . A solid electrolytic capacitor comprising a solid electrolyte layer comprising the electrically conductive polymer composition according to  claim 5 . 
     
     
         8 . The solid electrolytic capacitor according to  claim 7 , further comprising an anode body made of a valve action metal, and a dielectric layer formed on the surface of the anode body, wherein the solid electrolyte layer is formed on the dielectric layer. 
     
     
         9 . The solid electrolytic capacitor according to  claim 7 , wherein the valve action metal is at least one selected from aluminum, tantalum or niobium. 
     
     
         10 . A method for producing a solid electrolytic capacitor, comprising:
 forming a dielectric layer on a surface of an anode body made of a valve action metal; and   forming a first electrically conductive polymer layer by application or impregnation of the electrically conductive polymer suspension according to  claim 1  onto the dielectric layer, and by removing the dispersion medium from the electrically conductive polymer suspension.   
     
     
         11 . The method for producing a solid electrolytic capacitor according to  claim 10 , further comprising, before forming the first electrically conductive polymer layer,
 forming a second electrically conductive polymer layer on the dielectric layer by a chemical oxidation polymerization or an electrolysis polymerization.   
     
     
         12 . The method for producing a solid electrolytic capacitor according to  claim 10 , wherein in forming the first electrically conductive polymer layer, removing the dispersion medium is carried out at the melting temperature of the compound (A) or higher. 
     
     
         13 . The method for producing a solid electrolytic capacitor according to  claim 12 , wherein the temperature at which the dispersion medium is removed is 150° C. or higher and lower than 270° C. 
     
     
         14 . The method for producing a solid electrolytic capacitor according to  claim 10 , wherein an oxidation film covering the valve action metal is formed as the dielectric layer. 
     
     
         15 . The method for producing a solid electrolytic capacitor according to  claim 10 , wherein the valve action metal is at least one selected from aluminum, tantalum or niobium. 
     
     
         16 . The electrically conductive polymer suspension according to  claim 2 , wherein the electrically conductive polymer material comprises, as the electrically conductive polymer, a polymer obtained by polymerizing at least one monomer selected from a group consisted of pyrrole, thiophene, aniline and derivatives thereof. 
     
     
         17 . The electrically conductive polymer suspension according to  claim 3 , wherein the electrically conductive polymer material comprises, as the electrically conductive polymer, a polymer obtained by polymerizing at least one monomer selected from a group consisted of pyrrole, thiophene, aniline and derivatives thereof. 
     
     
         18 . An electrically conductive polymer composition obtained by removing the dispersion medium from the electrically conductive polymer suspension according to  claim 2 . 
     
     
         19 . An electrically conductive polymer composition obtained by removing the dispersion medium from the electrically conductive polymer suspension according to  claim 3 . 
     
     
         20 . An electrically conductive polymer composition obtained by removing the dispersion medium from the electrically conductive polymer suspension according to  claim 4 .